The present invention relates to information processing apparatuses, and more particularly to information processing apparatuses that display characters and images on a display device such as a liquid crystal display device and an organic material type display device.
Conventionally, in an information processing apparatus such as a mobile telephone or a mobile information terminal (PDA: Personal Digital Assistants) that is equipped with a display device such as a liquid crystal display device, an organic material type display device or the like, when characters and images are displayed on the display device, an operation processing device within the information processing apparatus (which corresponds, for example, to a host CPU in the mobile telephone and a main processor in the PDA) directly sends data to a display engine (which corresponds, for example, to a liquid crystal driver IC in the case of the display device being a liquid crystal display device) that drives the display device.
FIG. 6 shows a mobile telephone 50 that includes a host CPU 51, a display engine 52 and a liquid crystal display 53. The display engine 52 is composed of a driver IC for driving liquid crystal 54. The host CPU 51 and the driver IC for driving liquid crystal 53 are connected to each other by a host interface 55. The host interface 55 includes a chip select signal line, a read signal line, a write signal line, a data signal line, an interrupt signal line and the like.
The conventional mobile telephone 50 shown in FIG. 6 is limited to displaying characters and still pictures, and cannot execute personal information management software (PIM: Personal Information Management) or handle moving pictures. For this reason, the third generation mobile telephones that have been under development in recent years and digital cameras use a high-speed signal processing apparatus such as a DSP (Digital Signal Processors) or the like for their display engine in order to accommodate great data rates for transferring moving pictures and enable execution of PIM.
FIG. 7 shows a part of a structure of the third generation mobile telephone. In FIG. 7, the third generation mobile telephone 60 includes a host CPU 61, a display engine 62 and a liquid crystal display device 63. The display engine 62 is composed of a high-speed signal processing apparatus 64 such as a DSP and a driver IC for driving liquid crystal 65. The host CPU 61 and the high-speed signal processing apparatus 64 are connected to each other by a high-speed bus interface 66. The high-speed bus interface 66 includes a chip select signal line, a read signal line, a write signal line, a data signal line, an interrupt signal line and the like. Also, the high-speed signal processing apparatus 64 and the driver IC for driving liquid crystal 65 are connected to each other by a liquid crystal controller interface 67. The liquid crystal controller interface 67 includes a display data line for transferring display data that have been signal-processed.
However, for the third generation mobile telephone 60, substantial modifications are required over the host controller interface 55 as viewed from the host CPU 51 toward the display engine 52 of the conventional mobile telephone 50 shown in FIG. 6 to achieve the high-speed bus interface 66 as viewed from the host CPU 61 toward the display engine 62.
Also, in the third generation mobile telephone 60 shown in FIG. 7, the high-speed signal processing apparatus 64 needs to operate always without regard to whether it is in telephone conversation or in use of the PIM function, which results in a greater power consumption.
Furthermore, although the third generation mobile telephone 60 shown in FIG. 7 is equipped with the host CPU 61 and the high-speed signal processing apparatus 64, the OS and application are mounted right on the host CPU of the BBE(base band engine), which makes the role sharing by the two devices difficult. Also, when the specifications of hardware and software are changed, the entire system has to be modified.
The present invention has been made in view of the problems discussed above, and its object is to provide an information processing apparatus that can add high level functions while taking over the conventional host interface, by transferring commands from a CPU to a high-speed signal processing device such as a DSP or the like when moving pictures are received or a PIM is executed, and transferring instructions from the CPU to a driver IC for driving liquid crystal or the like when reception of moving pictures is completed or execution of a PIM is completed.
Also, it is an object to provide an information processing apparatus that can reduce the overall power consumption of the information processing apparatus, when reception of moving pictures or execution of a PIM is not conducted, by placing the high-speed signal processing device in a low power consumption state.
Furthermore, it is an object to provide an information processing apparatus that can display field intensity, time and the like on a liquid crystal display device or the like, by directly sending instructions from a CPU to a driver IC for driving liquid crystal or the like, while maintaining the high-speed signal processing device in a low power consumption state in cases other than reception of moving pictures or execution of a PIM.
Also, it is an object to provide an information processing apparatus that can control a high-speed signal processing device from a CPU.
Furthermore, it is an object to provide an information processing apparatus that can efficiently manage sharing of the roles of a CPU for a BBE and a CPU for an application.
To solve the problems described above, an information processing apparatus in accordance with the present invention is characterized in comprising: a display device that displays characters or images; a display driving device that has the display device display characters or images based on an instruction; an information processing section that receives a command, processes the command, and sends an instruction to the display driving device; a CPU that sends out the command addressed to the information processing section when a process by the information processing section is necessary, and sends out an instruction addressed to the display driving device in other cases; a control device that transfers, upon receiving the command addressed to the information processing section, the command to the information processing section, and transfers, upon receiving the instruction addressed to the display driving device, the instruction to the display driving device; and an interface device that receives the command or the instruction from the CPU and transfers the same to the display driving device or the control device, wherein the information processing section is equipped with an application for reproducing moving pictures and a resident software that exchanges data with the application and manages interrupt and buffer processing of the command, the CPU is equipped with a BBE (base band engine), and the control device bidirectionally exchanges the command between the resident software and the BBE.
Here, the information processing section is capable of taking an operation state or a low power consumption state, and capable of shifting to the low power consumption state when a command that indicates shifting to the low power consumption state is received or when a command that indicates shifting to the low power consumption state is not received for a specified period of time.
Furthermore, the information processing apparatus may be a mobile telephone or a mobile information terminal (PDA).
By transferring commands from the CPU to the information processing section, upon receiving moving pictures or executing a PIM, and transferring instructions from the CPU to the display driving device upon completion of reception of moving pictures or completion of execution of the PIM, high level functions can be added while taking over the conventional host interface. Also, by placing the information processing section in a low power consumption state when reception of moving pictures or execution of the PIM is not performed, the overall power consumption of the information processing apparatus can be reduced. Furthermore, since instructions can be directly sent from the CPU to the display driving device, the field intensity, time and the like can be displayed on the display device while maintaining the information processing section in a low power consumption state in cases other than reception of moving pictures or execution of the PIM. Also, the information processing section can be controlled from the CPU.
Also, by exchanging commands between the BBE and the resident software, an interface can be achieved between two modules. Also, by integrating interfaces into one, the modulability can be improved, such that, when the BBE or the application is modified, mutual influences inflicted on them can be restrained to the minimum. Also, when the functions are expanded, such a situation can be readily accommodated by adding commands. Furthermore, by using the resident software, high level operations that are well accommodated by the application can be performed.